Device for gluing the tail edge of logs of sheet material

Abstract: A device for gluing the tail edge of sticks or logs (10) of sheet material, such as paper or the like, comprising a positioning assembly (2) and a gluing assembly (3). The positioning assembly (2) comprises two rollers (4, 5) with a fixed centre distance, that can be operated in synchronism to position the log (10) correctly before its transfer to the gluing assembly (3), also comprising a pair of rollers (11, 12) with a fixed centre distance that can be rotated in synchronism. The roller (11) is a suction roller, which holds the edge (29) of the log, while the roller (12) can be moved vertically to tip the log (10) onto a glue distributing nozzle (19), which applies a layer of adhesive to the log itself, before it is discharged by rolling between a plane (20) and a belt (22) opposite, which presses on the log (10) causing the tail edge (29) to adhere to the glue-coated section of the log.

Description: The present invention relates to a device for gluing the tail edge of sticks or logs of sheet material, particularly paper. Industries manufacturing toilet paper, kitchen paper and the like, make use of so-called rewinding machines which, starting from large-sized rolls, produce sticks or logs that are subsequently cut transversely to the required length. As the log leaves the re-winding machine, the end of the paper must be glued down. This is achieved with special gluing devices (see e.g. US-A-3 393 105). The gluing devices known to the art are excessively complicated and costly, and do not always ensure perfect positioning of the log during application of the glue, thus affecting the quality of the result of the gluing operation. The aim of the invention is to provide a gluing device that guarantees perfect application of the glue and hence optimal gluing quality. Another aim of the invention is to provide a gluing device that can work at high speeds, and is thus capable of gluing logs that are delivered in rapid succession. Yet another aim of the invention is to provide a gluing device that is of simple construction and is therefore economical. These aims are achieved by the device for gluing the end of sticks of sheet material or logs, as described in the attached claims. Further characteristics of the invention will be made clearer by the detailed description that follows, which refers to a purely exemplary, and therefore non-restrictive, embodiment illustrated in the appended drawings, in which: Figure 1 is a schematic side view of the gluing device according to the invention; Figures 2, 3 and 4 are similar views to that in Figure 1, illustrating successive stages of the log-gluing operation; Figures 5 and 6 are schematic partial views with respect to those of the preceding figures, illustrating other two successive steps in the gluing operation. With reference to these figures, 1 indicates, as a whole, the device for gluing the tail edge of sticks or logs of sheet material, particularly paper. This gluing device can be situated right at the discharge point of a re-winding machine, in order to glue the tail edge of the logs as they leave the machine, or it can constitute a separate machine, that is fed by an accumulator where the logs are temporarily stored. The gluing device 1 comprises a log positioning assembly 2, situated upstream, and a gluing assembly proper 3. The positioning assembly 1 comprises a pair of rollers 4, 5 that can be operated in synchronism by means of a belt 6. During operation, the roller 4 has a fixed axis and is operated by the motor M by means of belt transmission 7. The roller 5 is supported between side plates 8 having their fulcrum on the axis of the roller 4, so that it can be lifted by means of a piston 9, maintaining a constant distance from the roller 4, which is obviously smaller than the diameter of the stick or log 10, shown in position between the pair of rollers 4, 5 in figure 1. The gluing assembly 3 also comprises a pair of rollers 11, 12, the former with a fixed axis and the latter with a mobile axis that can be moved by means of a piston 13 that acts on lateral supporting plates 14 of the roller 12, having their fulcrum on the axis of the roller 11. The roller 11 takes its motion from a motor M' through a belt 15 and transmits it in synchronism to the roller 12 by means of a belt 16. The mantle of the roller 11 has at least one perforated section 17, shown schematically in the appended figures 1, for suction of the edge of the log, as a result of the vacuum created in the roller by means of a suction duct 18 and a vacuum pump not shown. Immediately downstream of the roller 11, in the space between the roller mantle and the leading edge of an inclined plane or slide 20, through which the log is discharged, a glue applicator nozzle 19, having a continuous or broken end slit 21 for discharge of the glue, extends transversely substantially across the whole length of the log 10. Above the log discharge plane 20 is situated a continuous belt (or a plurality of belts), which winds around two end rollers 23 and 24, one of which is motorised, the lower branch 25 of which is substantially parallel to the discharge plane 20. The two rollers 23, 24 supporting the continuous belt 22 are mounted so as to slide vertically, so that the position of the belt 22 can be adjusted, for example by means of a hand-wheel 26, to adapt it to the diameter of the logs 10 which must be advanced between the lower branch 25 of the belt 22 and the discharge plane 20, as will be better described below. The gluing device according to the invention works as follows. The log 10, coming from the re-winding machine, or from an accumulator upstream, rolling on a chute 27 in the direction indicated by the arrow, falls from the space between the rollers 4, 5 of the positioning assembly 2, which are made to rotate, in the direction indicated by the respective arrows, for a predetermined time, in order to position the edge of the sheet material correctly. The rotation of the rollers 4 and 5 is then stopped and the piston 9 is operated in order to cause the roller 5 to be raised and thus the log 10 to be transferred, through a further chute 28, into the space between the rollers 11, 12 of the gluing assembly 3 (see figures 2 and 3). The log 10 thus reaches the gluing assembly with the tail edge always in the same position, so that rotation of the rollers 11, 12 in a clockwise direction (see arrows in figure 3) causes partial unwinding of the log 10, whose edge 29 adheres to the suction section 17 of the roller 11, in which a vacuum is created (figure 3). In this position, the rollers 11, 12 are stopped and the roller 12 is raised by operating the piston 13 (figure 4), in order to tip the log onto the discharge plane 20. When the log 10 is in contact between the roller 11 and the leading edge of the plane 20, adhesive is applied along one of its generatrices by means of the applicator nozzle 19. The log 10 is then "grasped" by the continuous upper belt 22, which presses it gently against the plane 20, making it roll towards the discharge and thus causing the tail edge 29 to adhere along the glue-coated portion of the log. Meanwhile, the roller 12 of the gluing assembly 2 has been lowered to the starting position (figure 5 and 6) and is ready to receive another log from the upstream positioning assembly 2. From what has been described the advantages of the gluing device according to the invention will be clear, said device being able to operate at high speeds, in that while the gluing assembly proper 3 applies the glue 10, a new log is prepared for gluing on the positioning assembly upstream 2. It is also clear that the gluing assembly according to the invention ensures accurate application of the glue on the log, and thus a constant quality of the gluing of the tail edge 29.

Claims: A gluing device for the tail edge of sticks or logs of sheet material, particularly paper, to be situated at the discharge point of a re-winding machine, or downstream of a log accumulator-feeder, characterised in that provision is made for a gluing assembly (3) comprising a pair of rollers (11, 12) with a fixed centre distance, that can be operated in synchronism, one of them (11) being a suction roller to hold the tail edge (29) of the log (10) in a predetermined position, established by a perforated section (17) of its mantle, and the other roller (12) being able to move in a substantially vertical direction, to tip the log onto a glue applicator nozzle (19) which spreads a thin layer of glue substantially along a generatrix of the log (10), means (20, 22) being provided to discharge the log (10) with a rolling action, making the tail edge (29) adhere to the glue-coated surface of the log itself. A device according to claim 1, characterised in that said means of discharging the log (10) consist of a rolling plane (20) and a continuous belt (22), which presses with one of its branches (25) substantially parallel to the plane (20) on the log (10). A device according to claim 2, characterised in that said belt (22) is positionable at an adjustable distance from the plane (20). A device according to claim 2 or 3, characterised in that said glue distributing nozzle (19) is situated in the space between the mantle of said suction roller (11) and the leading edge of said plane (20). A device according to claim 1, characterised in that said mobile roller (12) moves along a circular path with its centre on the axis of the suction roller (11). A device according to claim 1, characterised in that said rollers (11, 12) are made to rotate intermittently in the direction of unwinding of the log (10). A device according to any of the preceding claims, characterised in that upstream of said gluing assembly (3) is situated a positioning assembly (2), able to position the incoming log (10) correctly for subsequent transfer to the gluing assembly (3). A device according to claim 7, characterised in that said positioning assembly (2) comprises a pair of rollers (4, 5), with a fixed centre distance, that can be operated in synchronism, of which the one (5) furthest from the gluing assembly (3) is substantially vertically mobile to cause the log (10) to roll towards the gluing assembly. A device according to claim 8, characterised in that said mobile roller (5) of the positioning assembly (2) moves along a circular path with its centre on the axis of the other roller (4). A re-winding machine for sheet materials, particularly paper, comprising a device for gluing the tail edge of the log according to any one of the preceding claims.

Inventors: MATTEUCCI RENATO, MATTEUCCI, RENATO
Applicants: CONSANI ALBERTO SPA, ALBERTO CONSANI S.P.A
Application year: 1994
Main classification: B65H19
IPC codes: B65H19